1. Field of the Invention
The invention relates to an apparatus for production of an electromagnetically shielded connection between a plug arrangement (which has at least one plug) of a first unit and a socket arrangement, which has at least one corresponding socket, of a second unit, with the at least one plug and the at least one socket forming a plug connection when connected to one another.
2. Description of the Related Art
The problem of having to electromagnetically shield the connection between a plug and a socket, thus providing an electromagnetically compatible (EMC) plug connection, is known from the general prior art. Electromagnetic shielding is particularly important in the case of radio-frequency data links, that is to say when radio-frequency data transmission is intended to be reliably ensured.
In this context, shielded plug housings are known from the general prior art. In this case, the plug housing is connected to a metallic sheath on the supply cable. Once the plug and the socket, which is provided with a shielded socket housing, have been joined together, this results in electromagnetic shielding. A connection such as this is suitable for manual connection of two cables.
The electromagnetically shielded plug connection which is known from the prior art has, however, been found to be unsuitable when the connection between the plugs and the socket is intended to be made automatically or autonomously without any manual action. This may be the situation, for example, when an electronic unit is intended to be inserted into an adaptor or some other holding device and the plug connection is intended to be made automatically in the final position. In this situation, manufacturing tolerances and wear mean that the plug may not fit exactly in the socket. For this reason, at least the plug or the socket must be secured such that it can move, in order to compensate for the tolerances. However, a moving arrangement of a plug or of the socket according to the prior art has been found to be complex and susceptible to faults.
In order to make it possible to ensure data transmission with as little disturbance as possible, particularly in the case of radio-frequency data transmission, it is necessary for the housings of the two units which are intended to be connected to one another by means of the plug connection to be at the same electrical potential. This requires an electrical connection between the units or the metallic housings of the units. In this context, it is known from the general prior art for the metallically shielded plugs and sockets to be screwed to the housing of the appropriate unit. However, if the plug or the socket is arranged in a floating form and can thus move with respect to the housing of the unit, this connection is no longer reliable. For example, the floating arrangement means that dirt can enter between the contact points, so that an electrical connection is no longer made.
A further solution which is known from the general prior art is for an additional cable to be passed out of the housing of one unit and to be attached to the other unit. However, this solution is complex, susceptible to faults and does not allow an RF-shielded and EMC-shielded connection.
It is more complex to produce a reliable electromagnetically shielded plug connection as the number of plug connections and/or plug/socket pairs between the units to be connected together increases, particularly when floating suspension is required for this purpose.
Radio-frequency data transmission is used, for example, for so-called hard disk stores or flight data recorders in which the data obtained from a digital camera is stored during a photographic flight of an aircraft. This data may, for example, be image data, supplementary data relating to the images, such as mission data, system information or general information for post-processing. The flight data recorder is in general in the form of a bulk memory for the “digital mapping camera”.
Electrically and mechanically, every flight data recorder is an autonomous unit which is connected to the digital camera via an image data connection.
Every storage unit in the aircraft is mechanically secured, and is electrically connected to all the necessary cables in a further operation. After landing, the flight data recorder is removed, and the image data is copied to a ground-based bulk memory.
The known flight data recorders have the disadvantage that the plug connection between the flight data recorder and the cable which continues further is cumbersome, and is often very difficult owing to the confined spatial conditions in the aircraft. This is particularly true for high data transmission rates. Incorrect connection of cables can in this case lead to a malfunction. It is also particularly important in this case for the plug connection to be reliable, in particular to be resistant to vibration and impacts, since, otherwise, there is a risk of accidental disconnection of the connection owing to the aircraft movements which take place in flight.